This invention relates generally to control systems which employ a reader to control access to a restricted area. More particularly, the present invention relates generally to control systems which employ a reader for receiving data upon contact by a data carrier having a memory chip.
Control systems to which the invention relates employ automatic electronic controllers. The controllers respond to readers which have an input receptacle. A data carrier having a memory chip which includes a pre-established data code is manually inserted into the receptacle. Upon contact, the code is read into the controller. The controller may be employed to generate suitable signals in response to the code to, for example, provide access through an entranceway, to control inventory, to record the presence of an individual at a location, and numerous other applications.
A data carrier, such as a carrier marketed by Dallas Semiconductor as a DS 1990 Touch Serial Number, essentially functions as a key of an electronic serial number for automatic identification. The carrier includes a 64 bit ROM which stores data that is transferred serially upon contact with the reader. The carrier is coin-shaped and includes a durable stainless steel case. The carrier is typically mounted to a panel, a key ring, a clip, an adhesive pad, a photograph identification card or another accessory which facilitates portability and accessibility.
For applications wherein the controller functions to control access to an area, readers are installed adjacent to the entranceways. The reader electronically communicates with a programmable controller. The data carriers essentially function as keys. Upon contacting the key with the reader, the data from the carrier is serially input into the controller. Conventionally, the controller is programmed to accept or reject various data codes to correspondingly automatically provide access to the area. Typically, the controller generates a signal for releasing an electromagnetic lock or other electrically operated lock in response to a valid code or password. The time of entry and the identification of the individual entering may also be recorded by the controller.
A keypad is also commonly provided in conjunction with the reader. The keypad may function to input a pass code or a supplemental code, or may be used to program the controller. For some automatic control systems, it may not be desirable in terms of cost, headroom constraints, security and other factors to provide a keypad with each reader--especially for access control systems where a large number of users must pass through an entranceway without delay. Access to a restricted area may be obtained through a relatively compact reader which primarily includes a LED and an input port in the form of a receptacle for mating with the data carrier.
In some automatic control systems to which the invention relates, one side of the entranceway contains an entry set which includes a keypad as well as a reader while the opposite side of the doorway has a reader but no keypad. Both readers are connected with the controller, and programming is performed through the keypad. However, in numerous other systems--especially relatively low cost systems, none of the controlled sides of the entryway are provided with a keypad. While such systems may function in an efficient manner through use of a pre-programmed controller and a pre-established set of data carriers, flexibility for such a system is highly restrictive unless additional programming of the controller can be implemented on an ongoing basis.
For entry and monitor control applications, it is highly desirable that the controller be programmable to delete or add codes as the set of authorized users is expanded, contracted or changed. Several devices have been employed to accomplish such programming. Among such devices are a cordless touchpen, a hand-held computer and a PC keyboard. Each of the foregoing are all employed to input commands to program the controller. For a basic control access system, minimal programming capability ordinarily consists of adding or deleting passcodes as keys are lost or as new keys are added to the system.